PARSIPPANY, N.J. — Watson Pharmaceuticals and a partnering company are barred from launching a generic version of a blood-thinning drug under a federal court decision issued Friday.

Watson said the U.S. District Court for the District of Massachusetts issued a preliminary injunction preventing Watson and Amphastar Pharmaceuticals from marketing or setting Amphastar's generic version of Sanofi's Lovenox (enoxaparin sodium). The case was brought by Sandoz, the generics arm of Swiss drug maker Novartis that won Food and Drug Administration approval for generic Lovenox in July 2010.

Lovenox is used for preventing and treating conditions, such as deep-vein thrombosis and conditions related to angina and heart attack. Though Sanofi originally sought and won approval for the drug as a pharmaceutical drug, experts said its molecular complexity places it more in league with biologics. As such, the FDA's approval of Sandoz's version was seen as a milestone in the path toward an abbreviated approval pathway for biosimilars.

The Food and Drug Administration approved Amphastar's version of the drug in September, and Watson has the exclusive right to distribute it in the U.S. retail pharmacy channel. Watson said it was reviewing the court's decision and weighing options, which could include an appeal.